As confirmed last week on their Facebook page the British Embassy are issuing letters to any British National on Amnesty who wishes to convert inside the country to a new visa whereby it's impossible to return to your country of residence.
The letter will only be issued once and it's your responsibility to meet the requirements of the visa you wish to apply for.
My issue was I live in a Thailand but am unable to border bounce to apply for a Non O based on retirement at this time.
I got my letter this morning and they took 3 days to reply and send it to me. The letter is valid until 26th September. I didn't supply any information for option 4 other than to state my intention was to apply for retirement status.
The procedure to do so is below.
Email
Bangkok.DocumentaryServices@fco.gov.uk
Please provide evidence of:
1. Copy of the biodata page of your passport
2. Entry stamp in to Thailand
3. Proof of residence in a third country e.g. visa (if applicable)
4. Supporting documents relating to your long-term visa application e.g. marriage certificate, employment contract.